package com.gs.api.util;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

/**
 * @Description TODO AES加解密内容
 * @Author GuoShao
 * @Date 2020/9/26 18:12
 * @Version 1.0
 **/
public class AESUtil {

    private final static String SECRET = "https://github.com/guoshao99/";

    /**
     * AES 加密
     * @param str 加密的内容
     */
    public static String AESEncrypt(String str) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(SECRET.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            byte[] byteContent = str.getBytes("utf-8");
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);
            //二进制转换成16进制
            return parseByte2HexStr(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     * @param str 解密内容
     * @return
     */
    public static byte[] AESDecrypt(String str) {
        try {
            byte[] bytes = AESUtil.parseHexStr2Byte(str);

            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(SECRET.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(bytes);
            return result; // 加密
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将二进制转换成16进制
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    public static void main(String[] args) {
        String password = "123456";
        String str = AESUtil.AESEncrypt(password);//加密
        System.out.println("加密后:"+str);
        byte[] decrypt = AESUtil.AESDecrypt(str);//解密
        System.out.println("AES解密后:"+new String(decrypt));
    }
}
